How can I fix my engine?

I have an old Go-Ped made in Czecolosvokia called a 49CC JAWA Babbette. Kids didn't think one tank of gas without oil in it would hurt it. (WRONG)!!! Piston sized in cylinder, broken piston ring, company non existent. Piston, light damage, cylinder OK. I doubt that company made piston ring, so I guess it was selected out of a catalog by the designer at some period of time. My Question is where would I look for a new ring that might be currently used in a chainsaw, ATV, model airplane, weed eater, ETC. The piston measures 1.529 inches, 38. 96 MM
The ring measures 1.590 Inches, 40.00 MM in diameter. I realize that there are other critical dimensions to deal with, but I guess that this is a first stab at the problem and we can go from there. Thank you for your time and consideration --Jack--